A variety of systems and devices may be utilized to carry out hydrocarbon-related operations. These operations may include the drilling and completion of wellbores, recovering hydrocarbons such as oil and gas, transporting hydrocarbons across pipelines and flow lines and processing hydrocarbons. One system used in connection with hydrocarbon-related operations is a chemical treatment system that adds one or more chemicals into a well.
In some wells, and particularly older wells, the lower sections of the production tubing and the well casing as well as the lower areas of the near wellbore formation can become blocked by corrosion, scale, paraffin deposits, deposits of petroleum distillates and other undesirable deposits. These deposits may hinder the production of gas from the well by plugging perforations made in the well casing, thereby preventing the flow of gas into the wellbore. To combat this problem, treatment chemicals may be introduced into the wellbore. These treatment chemicals can include such things as soap, acid, corrosion inhibitors, solvents for paraffin and petroleum distillates, stabilizers and other known treatment chemicals. A number of techniques have been employed to deliver treatment chemicals downhole, most of which require the use of a pump to transfer chemicals from a reservoir to the well head.
One method of treatment is to continuously pump a small amount of treatment chemical into the well during production. The treatment chemical falls to the bottom of the well, where it mixes with other fluids and is drawn up with the liquid lifted by a lifting device. This continuous treatment approach usually requires a conduit, known as a capillary string, which may be banded to the production tubing to deliver the chemical, which may be mixed with water, to the bottom of the well. Mixing chemicals with a small amount of produced fluids and continuously or periodically returning the resulting mixture to the wellbore is another treatment method. Still, another method of chemical delivery is a batch treatment that involves pumping liquid treatment chemicals down the borehole using on a dead space below the perforations to retain residual chemical for a period of time. Finally, as is described in more detail herein, another treatment method involves the application of chemicals directly below, onto, or into, a plunger, and then using the plunger to push or deliver the chemicals down the well.
Conventionally, these methods use a pump to convey a treatment chemical from a supply to its application site. In some configurations, the pumps are powered by electricity or a fuel. Such pumps, which can include electric-powered or diaphragm pumps, may utilize fuel generator sets that introduce or produce exhaust gases that may have a harmful effect on the local environment. Moreover, the operation of pumps utilizing electrical power or combustion may be undesirable in certain environments where electrical sparks or heat may ignite volatile materials. Further, because these pumps can operate for extended periods, electrical energy or fuel must be continuously supplied or replenished. Because hydrocarbon-related operations can occur in relatively remote geographical regions, maintaining a supply of power for these pumps may be burdensome. Thus, chemical treatment operations may be made more efficient if one or more of these pump operating characteristics were minimized or eliminated.
It should be appreciated that the operating characteristics such as undesirable emissions and on-going power supply demands may be associated with numerous other systems and devices used in a variety of hydrocarbon-related operations and also in operations unrelated to the oil and gas industry. Thus, such systems and devices may also be made more efficient if one or more of these operating characteristics were minimized or eliminated.